Research Assessment #7

Phantom pain has always been a mystery to doctors, researchers, and patients alike. For those of you who don’t know what phantom pain is, it’s the feeling that people who have lost a limb have. This feeling consists of the painful sensation that one’s lost limb still exists. With this much said, we knew not much else about it. However, some researchers in Japan at the Osaka University had discovered an amazing thing about the treatment for the elusive phantom pain: it can actually help in restoring normal motor function to relieve the pain.

I have never lost a limb, so I don’t know the feeling of phantom pain. Even then, it still is quite fascinating to learn about. Our mind creates an impression that a missing limb exists! As much as I give my concerns to those who experience such a sensation, I would love to learn more about this condition and how it could be lessened if not fixed. To start off, the Japanese researchers made a prosthetic arm that works on the electric signals running through one’s body. This brain-machine interface (BMI) was put onto ten different phantom limb patients in order to measure the changes in their brain. For those of you who don’t know much about the brain, just know that the BMI decodes the electrical signal emitted from the sensorimotor cortex portion of the brain because that part of the brain deals with physical movement. So what the researchers hypothesized was that by attaching the BMI to the phantom limb patients should reduce pain. However, their hypothesis was proven wrong, in fact, almost completely wrong.

When the patients used the BMI as their arm and willed their arm to move, the sensorimotor cortex did indeed become more active in that more electrical currents were running back and forth, carrying out the information necessary to move the arm. This much was hypothesized as well and expected to happen. However, the training, instead of lowering their pain, instead significantly increased it. Based on this newfound information, the researchers took their research one step further. They reversed their thinking and used BMI training to associate the prosthetic hand with the intact hand. Basically, the prosthetic arm was made to work alongside the working limb. Based on this, the electrical signals made by the working hand could be replicated by the prosthetic arm. After testing this new type of training out, the results had shown that the pain experienced by the patients had actually lessened.

Well, this is not completely true. This is because five out of the ten patients had reported that this type of training or therapy had reduced pain more so than any previous therapy they had undertaken. This means that while this therapy is not proven to be absolutely effective in treating phantom pain, it suggests that further research in this direction can help cure the mystery that is phantom pain.